Long- and Short-Term High-Intensity Interval Training on Lipid Profile and Cardiovascular Disorders in Obese Male Adolescents

This study investigated the effects of short-term and long-term periods (8 and 16 weeks)
of high-intensity interval training (HIIT) on cardiovascular components, blood lipids, and 6-min
walking test performance in obese young boys (age = 16.2  0.7) with >34% body fat. The participants
were split into two groups: severe obesity (SOG; n = 17) and moderate obesity (MOG; n = 16). All
participants performed on a cycle ergometer for 16 weeks (3 times per week) of HIIT at 100% peak
power output at the ventilatory threshold and recovered at 50% of peak power. Except for BMI, both
groups improved all body composition measures after 16 weeks, with a higher percentage of change
(D) in SOG. The 6-min walking test increased in both groups (p < 0.001). Furthermore, cardiovascular
variables, blood lactate concentration at rest and after 5-min post-exercise, blood lipids, and insulin
concentrations improved significantly in both groups. After 16 weeks, MOG significantly improved
in HRpeak, blood glucose concentration, and rating of perceived exertion (RPE), but the percentage of
change (D) was higher in SOG for all the other variables. SOG showed a higher (D) waist-to-hip ratio,
maximum heart rate, resting heart rate, systolic blood pressure, blood lactate at 5-min post-exercise,
and triglyceride concentrations after 8 and 16 weeks of training. In conclusion, a long-term HIIT
program appears to be an appropriate training approach for obese boys with extra body fat. However,
considering the RPE values, short-duration training sessions should be planned.